Photographic emulsion containing a mercapto or thioxo group

ABSTRACT

PHOTOGRAPHIC LIGHT-SENSITIVE SILVER HALIDE MATERIALS ARE DESCRIBED INCLUDING A NON-LIGHT-SENSITIVE WATER-PERMEABLE COLLOID LAYER AND HAVING INCORPORATED THEREIN AT LEAST ONE ORGANIC COMPOUND COMPRISING A MERCAPTO GROUP OR A THIOXO GROUP SHOWING THIOXO-THIOL TAUTOMERISM, A GROUP RENDERING THE COMPOUND FAST TO DIFFUSION IN SAID COLLOID LAYER AND A GROUP RENDERING THE MOLECULE WATER-SOLUBLE OR ALKALI-SOLUBLE. THE SAID ORGANIC COMPOUND PREVENTS YELLOWING OF THE PHOTOGRAPHIC MATERIAL.

United States Patent 3,600,178 PHOTO-GRAPHIC EMULSEON CONTAINING A MERCAPTO 0R THIOXO GROUP Jozef Frans Willems, Wilrijk, Robrecht Julius Thiers, Brasschaat, and Frans Clement Heugebaert, Kontich, Belgium, assignors to Gevaert-Agta N.V., Mortsel, Belgium No Drawing. Filed Feb. 7, 1968, Ser. No. 703,572 Claims priority, application Great Britain, Feb. 15, 1967, 7,252/ 67 Int. Cl. G03c 1/48 US. CI. 96-76 Claims ABSTRACT OF THE DISCLOSURE Photographic light-sensitive silver halide materials are described including a non-light-sensitive water-permeable colloid layer and having incorporated therein at least one organic compound comprising a mercapto group or a thioxo group showing thioxo-thiol tautomerism, a group rendering the compound fast to diffusion in said colloid layer and a group rendering the molecule water-soluble or alkali-soluble. The said organic compound prevents yellowing of the photographic material.

The present invention relates to improved photographic light-sensitive silver halide materials, more particularly to photographic materials comprising agents that protect said materials against yellowing and that have no detrimental effect on the sensitivity of the photographic materials.

It is known that photographic light-sensitive silver halide materials, particularly stored photographic materials, are subject to yellowing. In some cases this yellowing is probably due to adsorption of finely divided silver particles, formed by reduction in more or less exhausted development baths, at the surface of processed photographic material where they are physically developed thus producing yellowing of the photographic material whereas in other cases this yellowing is most likely due to the deposition of finely divided silver in a non-light-sensitive colloid layer in water-permeable relationship with the emulsion layer resulting from the diffusion, during the coating process, of silver salts from the silver halide emulsion into the said water-permeable layer. During storage of these photographic materials the diffused silver salts are reduced to silver and, on development, if the developer comprises silver halide solvents, the dissolved silver salts are reduced on the silver nuclei of the said non-light-sensitive Water-permeable colloid layer thus producing yellowing of the photographic materials.

It has now been found that yellowing of photographic light-sensitive silver halide materials can be prevented by incorporating into the non-light-sensitive water-permeable colloid layers wherein yellowing is produced at least one organic compound comprising a mercapto group or a thioxo group showing thioXo-thiol tautomerism, a group rendering the compound fast to diffusion in said colloid layers and a group rendering the molecule water-soluble or alkali-soluble.

' Thus, in accordance with the present invention there is provided a photographic light-sensitive silver halide material comprising in a non-light-sensitive water-permeable colloid layer an organic compound as defined above.

The configuration of the part of the molecule bearing the silver salt forming thiol group or enolisable thioxo group is of minor importance. It sufiices that in addition to the said thiol group or thioxo group, are present in the molecule: a water-solubilizing or alkali-solubilizing group such as a sulpho group or carboxyl group in acid or salt form e.g. as salt from an alkalimetal or alkaline earth metal, ammonium, an organic base such as an amine, etc., as well as a group rendering the molecule fast to diffusion e.g. a radical comprising or consisting of an aliphatic radical with 8 to 20 carbon atoms in straight chain.

Since the compounds of use according to the present invention are fast to diffusion in the non-light-sensitive water-permeable colloid layers there is no risk at all of affecting the photographic characteristics of the silver halide emulsion layer.

It has been observed that these compounds can be incorporated in the non-light-sensitive water-permeable colloid layers in the required concentrations without giving rise to desensitization of the photographic material, contrary to most mercapto compounds comprising no wateror alkali-solubilizing group and/or no group rendering the molecule fast to diffusion, which are known to have a marked desensitizing effect when incorporated in photographic light-sensitive material. Moreover, the high watersolubility or alkali-solubility guarantees a homogeneous distribution of the anti-yellowing agent in the coating composition of the non-light-sensitive water-permeable colloid layer.

The compounds of use according to the present invention may be illustrated by the following classes of compounds:

(A) water-soluble or alkali-soluble aliphatic or aromatic thiols having a group rendering the molecule fast to ditfusion in the non-light-sensitive water-permeable colloid layers of the photographic material, for example:

(a) mercaptan acids (mercapto-carboxylic acids) comprising from 12 to 20 carbon atoms such as (1) a-mercapto-stearic acid, (2) a-mercapto-palmitic acid, etc.

(b) aliphatic or aromatic thiols e.g. obtained by reaction of low molecular thiols carrying a functional group such as an amino group or hydroxyl group with compounds carrying a sulphonic acid group or latent sulphonic acid group e.g. a sulphofluoride group, a group rendering the compound fast to diffusion and a functional group such as an isocyanate group or chlorocarbonyl group which latter functional group reacts with the functional group of the low-molecular thiol to form a chemical bond. An

example of such thiol is 3. s o Na HS-CH2CH O-(H1-NH OCI6H33 (B) Water-soluble or alkali-soluble heterocyclic nitrogen-containing thioxo-compounds showing thioxo-thiol tautomerism and having a group rendering the molecule fast to diffusion in the water-permeable colloid layers of the photographic material. These compounds may belong to the most divergent kinds of heterocyclic ring systems, amongst which:

Those of the l,2,4-triazoline-5-thione type as, for example:

CH2COOH Zl l Those of the beuzimidazoline-Z-thione, benzoxazoline- 2-thione and benzthiazoline-Z-thione type as for example:

The latter two compounds can be prepared by reaction of the amino-substituted benzoxaline-Z-thione or benzthiazoline-2-thione with 2-hexadecyloxy-S-sulphofiuorophenyl isocyanate or 2-heXadecyloxy-5-sulphofluoro-benzoyl chloride followed by saponification of the sulphofluoride group.

Those of the 1,3,4-oxaor thiadiazoline-Z-thione type such as e.g. the compound having the formula:

Those of the tetrazoline-S-thione type such as the compound haviug the formula:

Those of the triazine-thione type such as the compound having the formula:

Those of the 1,3,4-thiadiazone-2-thione type such as the compound having the formula:

The following is an illustration of how the anti-yellowing agents of use according to the present invention can be prepared.

PREPARATION 1 Compound 1 is prepared as follows:

76 g. (1 mole) of thiourea are added to 363 g. (1 mole) of a-bromostearic acid dissolved in 2 litres of ethanol. After having been refluxed with stirring for 4 hours a solution of 616 g. (11 moles) of potassium hydroxide in 2.4 litres of aqueous ethanol is added. Refiuxing is continued for 46 hours. The solution obtained is cooled to room temperature and poured into 3 litres of 4 N hydrochloric acid while stirring vigourously. The mixture obtained is heated to 80 C. whereby two layers form. By cooling gradually the supernatant layer solidifies. The underlying liquid layer is poured off and replaced by 2 litres of water. Then the mixture is again heated to 80 C. and cooled again so that the supernatant layer solidifies. This treatment with water is repeated til the wash-water has become neutral. The solidified oil is recrystallized from 3.5 litres of ethanol. Yield: 242 g. (0.76 mole). Melting point: 7475 C.

PREPARATION 2 Compound 3 is prepared as follows:

(a) N-(Z-hexadecyloxy 5 fluorosulphonylpheny1)-2- mercaptoethylurethane is prepared by allowing to react 22.05 g. (0.05 mole) of 2-hexadecyloxy-5-fluorosulphonylphenyl isocyanate with 40 ml. of fl-mercapto-ethanol while heating for 1 hour at C. The excess of ,B-mercaptoethanol is washed away with water and the residue is recrystallized from 100 m1. of ethanol. Yield: 23.5 g. (0.045 mole). Melting point: 5557 C.

(b) The sulphofluoride obtained is dissolved in acetone an saponified with sodium hydroxide in order to form the sodium salt of the corresponding sulphonic acid.

PREPARATION 3 Compound 4 is prepared as follows:

(a) 3 (p-aminophenyDA 4,2,4-triazoline--thione is prepared as follows:

182 g. (2 moles) of thiosemicarbazide and 330 g. (2 moles) of p-aminobenzoic acid ethyl ester are dissolved in 1 litre of a 2 molar solution of sodium methanolate. The mixture is refluxed for 16 hours whereupon 2 litres of water is added. The methanol is removed by evaporation and the mixture is filtered. By acidification of the filtrate with acetic acid 3-(p-aminophenyl)-A -1,2,4-triazoline-S-thione precipitates and said precipitate is then recrystallized from litres of Water. Yield: 127 g. (0.65 mole). Melting point: 260 C.

(b) 14.4 g. (0.075 mole) of 3-(p-aminophenyl)-A -1,2, 4-triazoline-5-thione are added to 24.15 g. (0.075 mole) of Z-hecadecenyl succinic anhydride dissolved in 750 ml. of acetone. The mixture is refluxed with stirring for 5 hours whereupon the precipitate formed is filtered by suction at room temperature and dissolved in an ammoniacal aqueous solution. The solution obtained is acidified with acetic acid and the product precipitated is recrystallized from 500 ml. of ethanol. Yield: 15 g. (0.03 mole). Melting point: 240250 C.

PREPARATION 4 Compound 5 is prepared as follows:

(a) 1 (m-fluorosulphonyl-p-hexadecyloxybenzoyl) thiosemicarbazide is prepared as follows:

1.387 g. (3 moles) of m-fluorosulphonyl-p-hexadecyl oxybenzoyl chloride are added to 819 g. (9 moles) of thiosemicarbazide dissolved in 7.5 litres of dimethyl formamide. The mixture is heated for 4 hours at 85 C. whereupon decolourizing carbon is added. The mixture is filtered and the filtrate is poured into litres of water. The precipitate formed is recrystallized from 9.5 1. of butanol. Yield: 878 g. (1.7 mole). Melting point: 215- 220 C.

(b) 865 g. (1.66 mole) of l-(m-fluorosulphonyl-phexadecyloxybenzoyl) thiosernicarbazide are suspended in 8.5 l. of acetone. This suspension is poured into 5 l. of 1 N sodium hydroxide. The acetone is removed by evaporation and the residual liquid is refluxed for 4 hours whereupon it is acidified with 670 ml. of concentrated hydrochloric acid. The precipitate formed is recrystallized from 13 l. of methanol. Yield: 810 g. (1.55 mole). Melting point: 260 C.

PREPARATION 5 Compound 6 is prepared as follows:

(a) l-(m fluorosulphonyl benzoyl) 4 hexadecylthiosemicarbazide is prepared as follows:

315 g. (1 mole) of 4-hexadecyl-thiosemicarbazide are dissolved in 1 litre of carbon tetrachoride whereupon the solution is added to 222.5 g. (1 mole) of m-fluorosulphonylbenzoyl chloride dissolved in 1 litre of carbon tetrachloride. The reaction mixture is refluxed for 3 hours whereupon the carbon tetrachloride is removed by evaporation. The residue is recrystallized from 8 l. of methanol. Yield: 300 g. (0.6 mole). Melting point: 70-80 C.

(b) 50 g. (0.1 mole) of 1-(m-fiuorosulphonyl-benzoyl)- 4-hexadecylthiosemicarbazide are dissolved in 2 litres of acetone whereupon the solution is poured into 1.2 l. of 0.25 N sodium hydroxide. The acetone is removed by evaporation and the residual liquid is refluxed for 4 hours whereupon it is acidified with ml. of concentrated hydrochloric acid. The precipitate formed is recrystallized 6 from 500 ml. of ethanol. Yield: 28 g. (0.055 mole). Melting point: 285-290 C.

PREPARATION 6 Compound 7 is prepared as follows:

(a) 3 (m fluorosulphonyl p hexadecyloxy-benzanilido)-A -1,2,4-triazoline 5 thione is prepared as follows:

13.8 g. (0.03 mole) of m-fluorosulphonyl-p-hexadecyloxybenzoyl chloride are added to 5.76 g. (0.03 mole) of 3 (p aminofenyl) A -1,2,4 triazoline 5 thione dissolved in 250 ml. of anhydrous dioxan. The reaction mixture is refluxed till no hydrogen chloride escapes any more and then cooled whereupon the precipitate formed is filtered by suction and recrystallized from 75 ml. of ethylene glycol monomethyl ether. Yield: 8.5 g. (0.014 mole). Melting point: 260 C.

(b) 6.18 g. (0.01 mole) of 3-(m-fluorosulphonyl-phexadecyloxybenzanilido A -1,2,4 triazoline 5 thione are suspended in ml. of acetone and then the suspension is poured into 40 ml. of 0.5 N sodium hydroxide. The mixture is refluxed for 4 hours whereupon the acetone is removed by evaporation and the residual liquid is acidified with 10 ml. 1 N hydrochloric acid. The precipitate formed is filtered. Yield: 6 g. (0.0094 mole). Melting point: 260 C.

PREPARATION 7 Compound 8 is prepared as follows:

(a) 22.05 g. (0.05 mole) of 2-hexadecyloxy-5-fluorosulphonylphenyl isocyanate are added to a solution of 9.6 g. (0.05 mole) of 3-(p-aminophenyl)-A -1,2,4-triazoline-S-thione in 250 ml. of anhydrous dioxan. The mixture is refluxed for 2 hours whereupon the dioxan is removed by evaporation and the residue is recrystallized from 500 ml. of a mixture of isopropanol and water (1:1). Yield: 20 g. (0.03 mole). Melting point: 220225 C.

(b) The sulphofluoride obtained is dissolved in acetone and saponified with sodium hydroxide to form the sodium salt of the corresponding sulphonic acid.

PREPARATION 8 Compound 9 is prepared as follows:

(a) 4 amino 3 heptadecyl A 1,2,4 -triazoline-5- thione is prepared as follows:

g. (0.56 mole) of thiocarbohydrazide are added to a solution of 200 g. (0.56 mole) of stearimidic acid ethyl ester hydrochloride in 600 ml. of anhydrous methanol. The mixture is refluxed for 2 hours with stirring whereupon it is cooled and the precipitate formed is recrystallized from 1.2 l. of acetic acid. Yield: 117 g. (0.33 mole). Melting point: 125-127 C.

(b) 303 g. (1.5 mole) of m-fiuorosulphonyl-phenyl isocyanate is added to a solution of 532 g. (1.5 mole) of 4-amino-3-heptadecyl-A -1,2,4-triazoline-5-thione in 4.5 l. of anhydrous benzene. The mixture is refluxed for 5 hours whereupon the benzene is removed by evaporation and the residue is recrystallized from 9 liters of a mixture of acetic acid and hexane (2:7). Yield: 575 g. (1.05 mole). Melting point: 164166 C.

(c) See (b) of Preparation 7.

PREPARATION 9 Compound 10 is prepared as follows:

(a) 7. 02 g. (0.03 mole) of m-fluorosulphonyl-benzoyl chloride are added to a solution of 10.62 g. (0.03 mole) of 4-amino-3-heptadecyl A 1,2,4triazoline-5-thione in ml. of anhydrous benzene. After the addition of 3.2 g. (0.04 mole) of pyridine, the reaction mixture is refluxed for 6 hours. The pyridine hydrochloride precipitated is filtered by suction and the benzene is removed by evaporation. The residue is recrystallized from ml. of a mixture of hexane and cyclohexane (1:1). Yield: 5 g. (0.0 1 mole). Melting point: 86-90 C.

(b) See (b) of Preparation 7.

7 PREPARATION 10 Compound 11 is prepared as follows:

47.8 g. (0.1 mole) of 3-sulpho-6-octadecylaminoaniline potassium salt is suspended together with 5.6 g. (0.1 mole) of potassium hydroxide and 100 ml. of carbon disulphide in 500 ml. of water. The mixture is refluxed with stirring for 2 hours whereupon the excess of carbon disulfide is removed by evaporation and the residual liquid is acidified with acetic acid. The precipitate is recrystallized from 500 ml. of methanol. Yield: 30 g. (0.057 mole). Melting point: 230-240 C.

PREPARATION 11 Compound 17 is prepared as follows:

(a) 7.6 g. (0.05 mole) of 2-methyl-2-isothiocyano-4- pentanone is added to a solution of 21.5 g. (0.05 mole) of 2-hexadecylthio-S-fluorosulphonyl-aniline in 100 ml. of dioxan. After the addition of 10 ml. of 5 N sulphuric acid the mixture is refluxed for 5 hours. The dioxan is removed by evaporation and the residue is recrystallized from 100 ml. of hexane. Yield: 11.5 g. (0.02 mole). Melting point: 93-95 C.

(b) See (b) of Preparation 7.

Beneficial effects in reduction of yellowing are obtained when solutions of the compounds of use according to the present invention are incorporated into the colloid coating compositions of the non-light-sensitive colloid layers in which the yellowing occurs. In these layers the op timum efiicacy of the compounds is achieved. The compounds of use according to the present invention are particularly suitable for preventing yellowing of photographic X-ray material for which purpose said compounds are incorporated in the gelatin protective antistress layer coated over the light-sensitive silver halide emulsion layer.

The amount of anti-yellowing agents employed as additives to non-light-sensitive colloid layers depends on the particular material and the desired effect and can vary within very wide limits. The optimum amount of anti-yellowing agent to be used can be readily determined by simple tests. Usually, the compounds are employed in amounts comprised between about 2 mg. and about 500 mg. per sq. m. of non-light-sensitive water-permeable colloid-layer.

Although according to present invention the anti-yellowing agents are particularly intended for the reduction of yellowing in photographic materials comprising lightsensitive silver halide X-ray emulsion layers the compounds according to the present invention may be used to prevent yellowing of any kind of photographic material comprising any type of light-sensitive silver halide emulsion layer e.g. spectrally sensitized and non-sensitized emulsion layers, X-ray emulsion layers and emulsion layers sensitive to infra-red radiation. The emulsions may be high-sensitive negative emulsions as well as rather low sensitive positive emulsions. Various silver salts may be used as light-sensitive salt e.g. silver bromide, silver iodide, silver chloride or mixed silver halides e.g. silver chloro-bromide or silver bromo-iodide.

The silver halides are dispersed in the common hydrophilic colloids such as gelatin, casein, polyvinyl alcohol, carboxymethylcellulose, alginic acid, etc., gelatin being however favoured.

The light-sensitive emulsions may be chemically as well as optically sensitized. They may be chemically sensitized by effecting the ripening in the presence of small amounts of sulphur containing compounds such as allyl thiocyanate, allyl thiourea, sodium thiosulphate, etc. The emulsions may also be sensitized by means of reductors for instance tin compounds as described in the French patent specification 1,146,955, filed Apr. 11, 1956 by Gevaert Photo-Producten N.V. and in the Belgian patent specification 568,687, filed June 18, 1958 by Gevaert Photo- Producten N.V., imino-aminomethane sulphinic acid compounds as described in the British patent specification 789,823, filed Apr. 29, 1955 by Gavaert Photo-Producten 8 N.V. and small amounts of noble metal compounds such as of gold, platinum, palladium, iridium, ruthenium and rhodium.

The light-sensitive silver halide emulsion layers may comprise compounds which sensitize the emulsion by development acceleration for example compounds of the polyoxyalkylene type such as alkylene oxide condensation products as described among others in U.S. Pats. 2,531,832 of William Alexander Stanton issued Nov. 28, 1950 and 2,533,990 of Ralph Kingsly Blake, issued Dec. 12, 1950, in UK. Pats. 920,637, 940,051, 945,340, filed May 7, 1959, Nov. 1, 1961, Oct. 23, 1961 all by Gevaert Photo- Producten N.V. and 991,608, filed June 14, 1961 by Kodak and in Belgian Pat. 648,710, filed June 2, 1964 by Gevaert Photo-Producten N.V. and onium derivatives of amino- N-oxides as described in French patent specification 1,498,724, filed Oct. 3, 1966 by Gevaert-Agfa N.V.

In general, these emulsion layers also comprise stabilizers for instance heterocyclic nitrogen-containing thioxo compounds such as benzothiazoline-Z-thione and l-phenyl- Z-tetrazoline-S-thione and particularly compounds of the hydroxy-triazolopyrimidine type (azaindolizines). They may also comprise mercury compounds as stabilizers, particularly in the case of high-sensitive emulsions comprising development accelerators of the polyoxyalkylene type. Suitable mercury compounds are, e.g. mercury oxide, the mercury compounds described in Belgian patent specifications 524,121, filed July 9, 1953 by Kodak and 677,337, filed Mr. 4, 1966 by Gevaert-Agfa N.V. and in UK patent application No. 55,445/66, filed Dec. 12, 1966 by Gevaert-Agfa N.V., basic salts of mercury corresponding to the formula:

wherein X represents an aryl radical, a heterocyclic radical, a hydroxyl group or an acid residue e.g. thiophene-mercury(Il) hydroxide and the compounds with formulae molecular addition compounds of mercury salts and organic sulphides such as the compound with formula:

mo ()JH HgOl;

s s 0 1r,

addition compounds of mercury salts and quaternary am monium salts such as the compound with formula:

C4119 +1 C IIgIIl -C4Hg aliphatic organo-mercury compounds having no ring structure in the aliphatic part of the molecule such as those described in U.S. patent specification 3,179,520 of Yashio Miura, Akira Kumai and Yosuka Nakajima, issued Apr. 20, 1965 and the compounds having the following formulae:

OCH

(I) O ONa Example 1 A coarse-grain gelatin brornoiodide (1.8 mole percent of iodide) emulsion of the X-ray type is prepared comas moistening agent. Two analogous X-ray materials are prepared with the difference however, that the protective layer also comprises an amount of compound 11 and compound 17, respectively as mentioned in the table below.

Samples of these three X-ray materials are then developed for 8 minutes at 20 C. in a developing bath having the following composition:

Water-800 ml.

p-Monomethylaminophenol hemisulphate-4 g. Sodium sulphite (cryst.)-130 g. Hydroquinone10 g.

Sodium carbonate (cryst.)120 g.

Potassium bromide-5 g.

Water to make 1000 ml.

After having stored the X-ray materials for 6 months, samples of said materials are once again developed in a same bath. The yellowing produced in the fresh materials and the stored materials is listed in the following table.

Example 2 A series of X-ray materials is prepared as described in Example 1, comprising, however, in the silver bromoiodide emulsion layer 2.0 mole percent of silver iodide and comprising in the gelatin antistress layer either no anti-yellowing agent or an anti-yellowing agent as listed in the following table. The materials are further treated as described in Example 1 giving the following results.

Yellowing in- Anti-yellowing Fresh Stored Material agent per sq. m. material material Material A No yellowing .S Very heavy yellowing.

B mg. of compound 1 do No yellowing.

C 100 mg. of copmound 5 do.. Do.

D 50 mg. of compound 6 do Do.

E 50 mg. of compound 7.. Do.

F 10 mg. of compound 9 do Do.

G- 50 mg. of compound 10 do Do.

What we claim is:

1. A photographic material comprising a support and at least one light-sensitive silver halide emulsion layer, characterized in that a non-light-sensitive water-permeable colloid layer of said photographic material contains at least one organic compound comprising a mercapto group or a thioxo group showing thioxo-thiol tautomerism, an aliphatic radical comprising from 8-20 carbon atoms rendering the compound fast to diffusion in said colloid layer and a carboxyl or sulpho radical in acid or salt form rendering the compound water-soluble or alkali-soluble.

2. A photographic material according to claim 1, wherein the said organic compound is an aliphatic or aromatic thiol or a heterocyclic nitrogen-containing thioxo-compound showing thioxo-thiol tautomerisrn.

3. A photographic material according to claim 1, wherein said organic compound is a mercaptan acid comprising from 12 to 20 carbon atoms.

4. A photographic material according to claim 1, wherein said organic compound is a heterocyclic nitrogen containing thioxo compound selected from a 1,2,4- triazoline-S-thione, a benzimidazoline-2-thione, a benzoX- azoline-Z-thione, a benzthiazoline-Z-thione, a 1,3,4-oxadiazoline-Z-thione, a tetrazoline-S-thione, a pyrimidinethioue, a triazine-thione and a 1,3,4-thiadiazine-2-thione.

5. A photographic material according to claim 1, wherein the said compound is present in a ratio of about 2 mg. to about 500 mg. per sq. m. of non-light-sensitive water-permeable colloid layer.

6. A photographic material according to claim 1, wherein said non-light-sensitive water-permeable colloid layer is a gelatin protective layer coated over the silver halide emulsion layer.

7. A photographic material according to claim 1, wherein said material is an X-ray material and the nonlight-sensitive water-permeable colloid layer is a gelatin protective layer coated over the silver halide X-ray emulsion layer.

8. A photographic material according to claim 1, wherein said material comprises a development accelerator of the polyoxyalkylene type.

9. A photographic material according to claim 1, 3,266,897 8/1966 Kennard et al. 9676 wherein said material comprises a stabilizer of the hy- 3,352,678 11/1967 NiShiO et a 96-76 droxy-triazolopyrimidine type.

10. A photographic material according to claim 1, FOREIGN PATENTS wherein said material comprises a mercury compound 5 948,481 2/1964 Great Britain 96-76 as stabilizer.

References Cited NORMAN G. TORCH-IN, Primarp Examiner UNITED STATES PATENTS J. L. GOODROW, Asslstant Examiner 3,008,829 11/1961 Clementi et al. 96-76 10 3,236,642 2/1966 Von Rintelen et a1. 96-76 96109; 250-65; 96--67 

